To meet the demands of ever-increasing data throughput, carrier aggregation (CA) between different frequency bands is becoming necessary. Differing spectrum allocations around the globe lead to a very large number of band combinations and put demanding performance requirements on the antenna interfaces for wideband receivers for inter-band CA. Sometimes multiple antennas are used, e.g. one for each band, but the small factor of mobile terminals severely limits the number of antennas. Splitting the antenna signal with filter banks and switches becomes very complex and costly due to the large number of band combinations (>90 currently).
Accordingly, new circuits for wireless communication capable of handling multiple frequencies are desirable.